All we need to feed everyone well and to stop the Earth being wrecked is farming that's based on well-directed science and good old-fashioned capitalism, all rooted in what might be called common morality – a true desire to take care of each other and of our fellow creatures.

The people in power – big governments, the corporations, the banks, and their attendant battalions of intellectuals and experts – will claim that this is what they have provided. Yet 1 billion out of 7 billion are undernourished; half our fellow creatures are in danger of extinction; the Earth as a whole is falling apart before our eyes – and it's due not to the fecklessness of humanity or the shortcomings of the Earth but to truly destructive strategies imposed from above. For present policy and all the science that goes with it are not designed to provide good food but to make as much money as possible in the shortest time so as to "compete" in the global market. That may sounds too childishly crude to be true, but alas it is the case.

Farming designed to maximise wealth is diametrically opposite in structure and technique to farming that is intended to feed people. Properly directed science tells us that we need farms that are as diverse as possible, meaning maximally mixed – for diversity is the key to resilience and long-term yield. Common sense tells us that in a finite world, farming must be low-input, which means as organic as possible. Mixed, low-input farming is complex and must be skills-intensive; there is little advantage in scale-up so the default farm size is small to medium. All this needs excellent science and technology – but small scale, and focused on biology rather than industrial chemistry.

If economists were concerned with on-the-ground reality they'd see that Britain now needs a million more farmers – at least 10 times the number at present; closer to 10% of the workforce than today's 1%. For a country with 2.5 million unemployed, including a million young people, many of them graduates, skills-intensive farming should be a godsend – not just a short-term expedient but the permanent base of the economy. Good disciples of Adam Smith would welcome small farms and small shops, too, because Smith's "invisible hand", which ensures fair play, works best if there's a host of providers, and doesn't work at all if there aren't.

But the dogmas of today are those of "finance capitalism", based on hypothetical money that is merely deemed to exist, which gave us the bubble that has now burst; and of neoliberalism, the so-called "free" global market, which demands ruthless, all-against-all competition (unless, of course, you compete well enough to fix the rules).

Apply these dogmas to agriculture and you don't get mixed, low-input, skills-intensive farms. You get maximum inputs of oil-based fertilisers and pesticides with minimum labour – which leads us to monoculture, because complexity is impossible without skilled husbandry. This is the absolute opposite of what common sense, 10,000 years of agricultural experience and good ecological science suggest we need.

Scientists are paid to give the impression that the status quo works. Successive governments beginning with Margaret Thatcher have closed Britain's network of publically supported agricultural research stations, and/or have gifted them to corporations. University departments have gone the same way. So scientists who seek seriously to be paid must work for corporations, even if they seem to be working for the public weal.

Hence the emphasis on genetically modified organisms, although GM technology has produced nothing of unequivocal value in the past 30 years that could not have been provided in the same time, without danger and at far less cost. For the point of GM is not to increase food security but to make a few rich companies richer and give them even more control. Governments like this because visible money is called GDP, which can be called "economic growth", and a few big companies are far easier to deal with than hordes of stroppy farmers, and there's always the lure of a place on the board.

This week the powers that be are meeting, as they do every year, for the Oxford Farming Conference, to celebrate the triumphs of industrialised farming. This year, though, even they have noticed that all is not well – and feel that the obsessive focus on wealth for wealth's wake and the corporatisation that goes with it may be in part to blame. Their theme this year is "power".

Yet the ORC is financed by the very people who have seized the power, and they cannot conceive of giving it up. The discussion we need to have is left to the Oxford Real Farming Conference, held at the same time on the opposite side of the road, which was set up three years ago to provide the antidote to the blandishments of officialdom. It's continued by the Campaign for Real Farming, where everyone – but especially farmers – are invited to say what really needs to be done, and to show how. For if the powers that be won't do the job then we, the people at large, just have to do it ourselves. As a matter of urgency we need nothing less than a people's takeover of the world's food supply.

• The Oxford Real Farming Conference is at Magdalen College, Oxford, on 5/6 January 2012. Colin Tudge's latest book, Good Food for Everyone Forever, is available now from Pari Publishing